Secondary xenoxy-alkyl amines



Patented Oct. 15, 1940 UNITED STATES SECONDARY xENoxY-AilKYL AMINEs 1 "Francis N. Alquist and Harold R. Slagh, Midland} Mich, assignors to The Dow Chemical Com 1 pany, Midland, Mich., a corporationotMichi- I g an No Drawingl Application July 27,1938,"

SerialNo. 221,605

6 Claims. (014501-45 1 This invention concerns certain secondary amines having the formula order that the major product of reaction may bethe secondary amine compound. The reaction is carried out in the liquid phase under atmospheric pressure, or in .a high pressure reactor under autogenous pressure, stirring being maintained throughout the process until the condensation is complete. The preferred temperature is dependent upon the particular reactants employed and is usually between about 125 C. and the decomposition temperature of the reaction mixture, although somewhat lower temperatures will sometimes accomplish the condensation. On completion of the heating step, the reaction mixture is washed with aqueous alkali or other-. wise neutralized to liberate the free amine compounds. While the crude product so obtained has been found of. value as an acid inhibitor, such mixture may befractionally distilled under reduced pressure to obtain the desired secondary amines in substantially pure form. These compounds are for themost part high boiling oils diflicultly soluble in water, somewhat soluble in most common organic solvents-and having a characteristic amine odor. The resinous tars obtained as distillation residues following the recovery of the secondary. amines consists of a mixture of tertiary amine products, which decompose upon attempted distillation.

Thehydrochlorides of the secondary amine compounds obtained as described above may be readily prepared by dissolving the secondary amine in a suitable organic solvent, e. g. benzene, petroleum ether, and the like, and thereafter bubbling dry hydrogen chloride through the solution to precipitate the desiredamine salts. These hydrochlorides are generally solid crystalline compounds readily separable from such solvent suspension by filtration.

If desired, the condensation may be carried out in the presence of an inert organic solvent such as'xylena'toluene, and the like. Also, a J

small amount of copper or potassium iodide catalyst may be included inth'e reaction mixture to accelerate the speed of reaction although-this is not required. Similarly, inorganicalkalies, such as sodium carbonate, calcium oxide, etc., may be employed to-"ex-pedite the'condensa'tion.

The expressions xenyl, xenoxy, and xenol, as herein employed, refer to diphenyl and phenyl-pheno'x'y radicals and to the phenylpl'ienols,frespectively; and include such radicals and compound wherein the benzene nuclei may be substituted by alkyl or halogen. The term primary amine refers to any-mono-alkyl, cycloalkyl, aryl, aralkyL' hydroxy-alkyl, hydroxy-aryl amine, and the like, as well as to amine compounds of the type'of naphthyl amine, benzidine, furfuryl amine, etc. "The" expression does not include such compounds as the carbo'xylicf'a cid amides, amino acids, etc. i

The xenoxy-alkyl halides'employed as reactants in thepreparation of our new secondary amines and their hydrohalides may be prepared by the reaction of an alkylene dihalide with an alkali I metal xenolate, e. g. sodium-ortho-phenylphenolate. The xenoxy-alkyl .halides; are all high boiling compounds andvary in characteristicfrom viscous oils to high-melting solids.

The following examples describe in detail several adaptationsof our invention; but are not to be construed as limiting....the samea,

Example 1 A mixtureof 116 grams (0.5 mol) of beta-2- xenoxy-ethyl chloride (melting point 55.2 C., boiling point;1'74" -176 C. at millimeters pres sure) and-100=grams (1:15'mols) of normal-amyl amine was refluxed for.28 hours at temperatures increasing from 105 to 140 C. The reacted mixture was then cooled and 220*mil1iliters of 10 per cent aqueous sodium hydroxide solution mixed therewith to liberate a mixture of freeamine compounds asa water-immiscible oil. oil was taken up in benzene and fractionally distilled, whereby there was obtained 111 grams of (beta-2-xenoxy-ethyl) (normal-amyl) -amine as an amber oil having a characteristic; amine odor, a specific gravity of 1.011 at /25 0., and boiling at approximately 200 C. at 0.4 inch pressure. This compound has the following formula sisted of 19 grams of a viscous, brown oil somewhat soluble in benzene, and boiling with decomposition at temperatures above 25 C. at 0.4 inch pressure. This mixture was high in tertiary amine compounds.

A portion of the above secondary amine compound was dissolved in petroleum ether. and reacted with an excess of dry hydrogen chloride,

whereby there was obtained (beta-Z-xenoxyethyl) -(normal-amyl) -amine hydrochloride as a white, crystalline product melting at 119 C.

Example 2 102 grams (1.1 mols) of aniline, 116 grams (0.5 mol) of beta-2-xenoxy-ethyl chloride, and 14 grams (0.25 mol) of calcium oxide were heated at 182184 C. for 6 hours, the reaction mixture being continually agitated over this period. The

crude reaction product was then cooled to room.

temperature, diluted with an excess of water, and extracted with benzene. The benzene extract was dried and fractionally distilled, whereby there was obtained 72 grams of (beta-Z-xenoxyethyD-(phenyD-amine having the formula This compound was an amber-colored, viscous oil boiling at 215225 C. at 0.18 inch pressure, and having a specific gravity of 1.123 at 25/25 C.

A portion of this product was dissolved in benzene and reacted with an excess of dry hydrogen chloride, whereby a White, crystalline precipitate was formed. This product was filtered out of the benzene medium and recrystallized from benzene to obtain (beta-21-xenoXy-ethy1) -(phenyl) -amine hydrochloride as a white, crystalline product melting at C.

Example 3 In a similar manner 0.5 mol of beta-3-xenoxyethyl chloride (boiling at 1'l9181 C. at 5 millimeters pressure) was mixed with 1.1'mols of aniline and heated at 198237 C. for 19 hours. The reaction mixture was neutralized with aqueous sodium hydroxide, and the crude amine product fractionally distilled, whereby there was obtained 76 grams of (beta-3-xenoxyethyD-(phenyl) -amine having the formula This product boiled at 1681'l5 C. at 0.2 inch pressure, and was a light yellow oil which crystallized on long standing and had a characteristic amine odor.

Example 4 116 grams (0.5 mols) of beta-2-xenoxy-ethyl chloride, and 157' grams (1.1 mols) of alphanaphthyl amine were mixed together and heated at 200225 C. for 18 hours. The crude reaction product was cooled to room temperature, neutralized with an excess of aqueous sodium hydroxide, and the resulting oil layer taken up in chloroform and fractionally distilled. 76.0 grams of (beta-Zr-xenoxy-ethyl)-(alpha-naphthyl)-amine was thereby obtained, boiling at 2602'74 C. at 0.1 inch pressure. This compound is an amber-colored, viscous liquid at room temperature and has the formula Example 6 116 grams (0.5 mol) of beta-Z-xenoxy-ethyl chloride and 120 grams (1.1 mols) of 2-amino phenol were dissolved in milliliters of xylene and the solution refluxed at 146157 C. for 40 hours. 220 grams of a10' per cent aqueous sodium hydroxide solution was then shaken with the reacted mixture and the xylene layer separated. Upon distillation of the xylene solution there was obtained 71 grams of (beta-2-xenoxyethyl) -(2i-hydroxy-phenyl)-amine as a thick, straw-colored sirup boiling between 210 and 224 C. at 0.2 inch pressure. This compound is soluble in alcohol and benzene and has the formula Example 7 116 grams (0.5 mol) of beta-2-xenoxy-ethyl chloride and 128 grams (2 mols) of mono-ethanol amine (95 per cent) were mixed together and heated at temperatures gradually increasing from to 205 C. for 16.5 hours. The crude reaction product was then cooled to room temperature and neutralized with an excess of aqueous sodium hydroxide. The alkaline mixture was extracted with benzene and the benzene extract fractionally distilled, whereby there was obtained 84 grams of (beta-Z-xenoxy-ethyl)-(beta-hydroxy-ethyl) -amine having the formula This compound is a straw-colored oil boiling at 220 22'l C. at 0.1 inch pressure and tending to crystallize out upon long standing.

Example 8 A mixture of 46.5 grams (0.2 mol) of beta-3- xenoxy-ethyl chloride, 42.8 gn'ams (0.4 mol) of meta-toluidine, and 5.6 grams (0.1 mol) of calcium oxide was heated at 200215 C. for 6 hours with agitation. The reaction mixture was then diluted with water, extracted with benzene, and the benzene extract dried and fractionally distilled to remove the excess of unreacted toluidine. The residualbrown oil was taken up with benzene and reacted with dry hydrogen chloride, whereby the secondary amine salt precipitated from solution. This precipitate was separated, washed with benzene and ether, and dried, whereby there was obtained 39 grams of (beta-3- xenoxy-ethyl) (meta-tolyl) -amine hydrochloride as a light crystalline product melting at 167 C. Upon recrystallization from 95 per cent ethanol, this compound was obtained as a white powder melting at 168 C.

In a similar manner, other xenoxy-alkyl halides, such as the bromides and iodides, may be reacted with primary amines to form secondary amine compounds falling within the scope of this invention. Representative of the xenoxy-alkyl halides which may be so reacted are beta-Z-xenoxy-ethyl bromide, a white, crystalline solid melting at 665 C. and boiling at 170-1'75 C. at 5 millimeters pressure; beta-l-xenoxy-ethyl chloride, a crystalline compound melting at C. and boiling at 163165 C. at 3 millimeters pressure; (beta-methyl) (gamma-2-xenoxy) -npropyl-chloride, an oil boiling at 1'701'73 C. at 5 millimeters pressure; beta- 2-(5-ch1oro xenoxy) -ethyl chloride, a viscous oil boiling at 149- 150 C. at 3 millimeters pressure; beta-2-(5-isopropyl-xenoxy)-ethyl chloride, an oil boiling at 150153 C. at 2 millimeters pressure, and having a specific gravity of 1.093 at 20 0.; etc. Other similar compounds which may be employed are omega-2-xenoxy-n-amyl-chloride, gamma-2- (5 -bromo-xenoxy)- propyl bromide, beta-2-(5- tertiary-butyl-xenoxy)-ethyl chloride, beta-2- xenoxy-ethyl iodide, beta-4-(2.,6-dimethyl-xenoxy)-ethyl chloride, and the like. Among the amines which may be reacted with such xenoxyalkyl halides are ethylamine, propylamine, octylamine, octadecanylamine, cyclohexylamine, benzylamine, cyclohexylethylamine, phenylethylamine, allylamine, furfurylamine, benzidine, anthramine, paratoluidine, 2-amino-diphenyl, para-chlor-aniline, and the like. The hydrochlorides of the secondary amines obtained by the reaction of the above xenoxy-alkyl halides and primary amines may be readily prepared substantially as described in the foregoing examples.

Small amounts of the secondary amines such as described in the foregoing examples may be added to aqueous acid solutions as corrosion inhibitors. (beta-2-Xenoxy-n-propyl) -(phenyl) -amine in 10.5 per cent hydrochloric acid was prepared. Weighed iron strips of 6.75 square inches surface area were suspended in this solution and also in a control solution of 10.5 per cent hydrochloric acid to determine the inhibiting effect of the amine. After 16 hours at room temperature, the test specimens suspended in the control solution were found to have lost 0.820 and 1,287 grams in weight, respectively. Similar test specimens suspended in the hydrochloric acid-amine solution showed a weight loss of only 0.030 and 0.027 grams, respectively, after 16 hours. The presence of the amine fraction in the aqueous acid solution accounted for a reduction in excess of 97 per cent of the total weight lost by corrosion. In a similar test, a 1 per cent mixture of (beta-2- xenoxy-ethyl) (alpha-naphthyl) -amine in 10.2 per cent hydrochloric acid was compared with For example, a 1 per cent solution of a control solution of 10.2 per cent acid to determine the inhibiting efiect of the amine. The two metal strips suspended in the control solution lost 0.888 and 0.819 gram, respectively, while those suspended in the solution containing the secondary amine fraction showed a loss of only @Cki ORN-R" wherein R represents a lower alkylene group and R" represents an aryl radical.

3.. A compound selected from the group consisting of (1) secondary amines having the formula R-0R-NR" wherein R represents a xenyl radical, R represents a lower alkylene group, and R represents a member of the group consisting of hydrocarbon and halo-aryl radicals, and (2) the hydrochlorides of such secondary amines.

4. A secondary amine having the formula 5 RORN-R wherein R represents a xenyl radical, R represents a lower alkylene group, and R represents a member of the group consisting of hydrocarbon and halo-aryl radicals.

5. A secondary amine hydrochloride having the formula i RO-R' R".HCl

wherein R represents a xenyl radical, R representst a lower alkylene group, and R" represents a member of the group consisting of hydrocarbon and halo-aryl radicals.

6. A secondary amine having the formula R-OR'NR" wherein R represents a xenyl radical, R' represents a lower alkylene group, and R" represents a hydrocarbon radical.

FRANCIS N. ALQUIST. HAROLD R. SLAGH. 

